For this exercise you need to use the formula for calculate the distance between two points:
[tex]d=\sqrt[]{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
In this case you know that the points are:
[tex]\begin{gathered} Q\mleft(-4,6\mright) \\ R(8,6) \end{gathered}[/tex]
So you can set up that:
[tex]\begin{gathered} x_2=-4 \\ x_1=8 \\ y_2=6 \\ y_1=6 \end{gathered}[/tex]
Substitute the corresponding coordinates into the formula and then evaluate, in order to find the distance from point Q to point R:
[tex]\begin{gathered} d_{(QR)}=\sqrt[]{(-4-8)^2+(6-6)^2} \\ d_{(QR)}=\sqrt[]{(-12)^2+(0)^2} \\ d_{(QR)}=\sqrt[]{144} \\ d_{(QR)}=12 \end{gathered}[/tex]
The answer is;
[tex]d_{(QR)}=12[/tex]
